Found the problem and fixed it
. #3 rear intake valve rocker arm roller seized to the pin and wore a flat spot about 3/16th of an inch down. I replaced the rocker and the hydraulic lash adjuster, reassembled the engine and it runs quiet
I replaced the spark plugs while I was at it, well seven of eight so far... The other day I attempted to pull #1 plug and it wouldn't budge so I put some nutcracker in it and tried #2, it came loose so I checked it and reinstalled it with antisieze. I drove about 300km and then tried the plugs again yesterday. #1,2,5,6,7,8 came loose no problem but I was impatient and broke #4 off
and #3 wouldn't budge. It took me 3 hours, about six different easy outs, lots of Nut Cracker and Deep Creep, various extensions, sockets, misc other tools, an air hammer and some profanity to get it out. I was so relieved. #3 hopefully will come out in a few days once the Nut Cracker has been able to soak in (hopefully
I'm surprised at how little the torques are for the hardware on these engines, 96 in/lb for the cam bearing caps, 120 in/lb for the spark plugs, wow
, I thought the cam caps had been improperly torqued they were so loose. Obviously the person that installed the plugs hadn't looked up the torque...
Hopefully this helps someone out there and thank you for your input Nojoke327, I do have codes P0420 and P0430 come up occasionally, It seems to be a random thing so far. Freeze frame data seems to show it setting the codes when the truck is coasting and it appears to set both codes at the same time. After replacing the plugs yesterday the truck started perfectly, usually it seems to stumble when it's cold. I'm going to monitor it and maybe ask about it in later on.